Role of polyethylene materials in our life.
it is possible to Protect food from hit in them harmful substances, correctly using protective properties of polymeric materials (for example: food wrap, packages pvd). Important not only to grow up a big crop, to clean it, but that is especially important, to keep it (not only from the point of view of quantity, but also quality) up to the moment of the use of food. the Problem of preservation of food occupied with
the person long ago, at different times it differently was solved also the different people. Ancient Indians, for example. Inhabiting South America, dried meat on the sun, then pounded it between stones, adding honey, berries, herbs.
pressed the Received mix and stored in leather bags. This product can be considered as a prototype of modern concentrates with peculiar technology and packing. Since ancient times inhabitants of Siberia prepared flour which it was possible to store quite long time from dried fish.
the Problem of storage of food arose due to the need to prepare food stocks for itself, the tribe, equipment of expeditions, equipments of army, etc.
In 1857 - in Lille (France) were made the report by Louis Pasteur who became subsequently well-known who claimed that “... beer, wine and milk are spoiled by beings invisible to an eye - microbes. They cause disastrous process which leads to damage of products... His compatriot cook Nikola Francois Apper of 1795 became as now speak, a winner a competition on the best way of long storage of products. He in essence, for the first time offered and described preparation of canned food.
formation and development of microbiology allowed to bring further the scientific base on; various processing methods conservation of food. It turned out that the activity of microorganisms promoting damage of food is shown under conditions of observance certain temperature re a press, a certain humidity, lack of the substances which are aggressively entering interaction from substance mi of which microorganisms consist and those conditions do not correspond to those which are necessary for development of microorganisms, the last perish likbo their activity temporarily stops and therefore, also process of damage of food stops.